I’ve got several nieces and nephews (and more through my husband)
How often I see them depends on how close they are to where we live and how well I/we get on with their parents
My eldest sister has 3 DC who are now all teens / pre-teens. They live about 20 minutes away and we see them at least once a week, more during the school holidays as they often come and stay as their parents work shifts and we are around more to do things. I’m very close to my sister and we’ve been very involved with the kids since they were young - I still take my DNiece to an activity once a week as it doesn’t fit with her parents shift patterns very well.
My next oldest sister and her family (2 DCs aged 8-10) live about 4 hours away. I travel a lot for work and they live close to an airport I often need to use, so I’ll see them then. Otherwise it’s usually once every school holidays.
My brother and his family (1 DC pre-school aged) live a couple of hours away. We see them about once a month as they visit my parents who live close by.
My SiL has three DC who are teens but live abroad. We see them every summer when they visit the UK and we try and go and see them once a year where they live.
My BiL has two DC (5-7) and live about 15mins away. We see them about once a week in school time and do childcare for much of the school holidays as we both work flexibly and from home, so can see them every day for stretches of time.